Optical cables are known in which a plurality of optical fibers are disposed inside a press-wrapping tape processed into a helical shape (a circular cylinder shape). In Patent Literature 1, press-wrapping tape is formed into a helical shape by passing the press-wrapping tape through a former having a helical shaped groove including an overlap section.
Note that Patent Literature 2 and 3 also disclose formers (also referred to as tape formers) for forming press-wrapping tape.